To discuss the influence of the development degree of structural plane on the location selection of high-level radioactive waste repository, the rock mass of Suanjingzi area in Beishan, Gansu Province, was taken as the research object, and the statistical characteristics, such as the joint occurrence, density, spacing, trace length, fault occurrence, width of fault zone and thickness of fault gouge, were obtained through the mathematical statistics based on the geometric characteristic investigation of joints and faults in the superficial rock mass. Then, a multi-scale structural surface comprehensive evaluation index was proposed to evaluate the structural plane development in the superficial rock mass. The results showed that there were 4 and 5 dominant joint groups around BS22 and BS23 boreholes, and joints obeyed the normal distribution. The midpoint surface densities of joint traces around BS22 and BS23 boreholes were 0. 037 m^-2 and 0. 035 m^-2 respectively, and the average trace lengths were 20. 38 m and 17. 39 m respectively. The fault F1 was interpreted as 35°∠85°, with an extension length of 4. 49 km. The structural plane of rock mass around the BS22 drill hole was less developed and more suitable for the construction site of high-level radioactive waste repository than the BS22 borehole.